The invention relates to a method of disposing of waste sludge such as industrial sludges (for example, poisonous metallic sludges) and sewage sludge in an environmentally sound manner. In the past the disposal of such sludges has been a major problem confronting municipalities and other sewage treatment plant operators. Disposal techniques have included incineration, landfilling, composting, or merely dumping the sludge into waterways. As opposed to most of the prior art techniques, according to the teachings of the present invention, the sludge is treated as a resource rather than as a disposal problem, and a valuable end product is produced thereby.
In the making of ceramic articles, and especially in the making of insulating bricks, the use of sewage sludge with clay to form the material from which the ceramic articles are to be made does not affect the desirable physical properties of the final article produced. In fact, in the production of insulating bricks, organic material is often conventionally added to the clay and then during firing in a kiln the organic material is oxidized to produce a final product with good insulating properties.
In the past, there has also been a problem in disposing of used oil from automobiles and other vehicles, and from various industrial machinery and processes. If the oil is released into the environment, pollution will result. Although recycling of such oil is feasible under many circumstances, harmful chemicals may be released during the recycling process, and market demand for the end product is not always sufficient to justify the expense necessary to set up a recycling plant. Again according to the teachings of the present invention the used oil is utilized as a resource rather than treated as a disposal problem. When mixed with clay and sewage sludge, it reduces the odor associated with the sludge and assists in firing the kiln. In addition, burning of used oil may be the primary method of firing the kiln.